1. Technical Field
The present invention relates to a robot, a controller, and a robot system.
2. Related Art
For example, as industrial robots, horizontal articulated robots (SCARA robots), vertical articulated robots, etc. including robot arms have been used in related art. For control of the robots, information by sensors in the robot arms is used.
In the robots in related art, the number of sensors has been smaller and the sensors have been limited to angle sensors. On the other hand, in recent multifunctional robots, for example, impedance control, damping control using inertial sensors such as angular velocity sensors (gyro sensors) etc. are performed. Further, the number of sensors in the robot arm tends to increase with reduction in size, higher reliability, lower price of the sensors. Furthermore, the number of wires in the robot arm tends to increase by communication with the inertial sensors, end effectors (hand units), etc.
For wires connected to the sensors etc. in the robot arm, parallel wiring is used (for example, see Patent Document 1 (JP-A-2002-79487)). Further, a robot controller including an angle sensor and an angular velocity sensor as inertial sensors is disclosed (for example, see Patent Document 2 (JP-A-2005-242794)). In the robot that damps the robot arm using the inertial sensors, a vibration suppression effect largely varies depending on the locations and the number of the inertial sensors. Therefore, for suppression of the vibration of the robot arm, the locations and the number of the inertial sensors are important.
Further, the robots have been used in various fields such as industrial fields including assembly of industrial products. The robot includes a leg in contact with a surface such as a floor or ground on which the robot is installed, a torso supported by the leg, and an arm attached to the torso (for example, see Patent Document 3 (JP-A-2005-161414)). The torso is connected to the leg via a waist pivot and rotatable with respect to the leg in the circumferential direction of the waist pivot. The arm includes links etc. and movable with respect to the torso. The arm is driven and controlled by a control system electric device to execute predetermined processing. In Patent Document 3, the control system electric device is concentrated in the torso to avoid the leg etc. in order not to hinder motion performance of the leg etc.
However, in the case where the sensors etc. are connected via parallel wiring as in Patent Document 1, a problem of increase in the number of wires arises. The increase in the number of wires blocks downsizing of the robot. Particularly, in the robot that damps the robot arm using the inertial sensors as in Patent Document 2, the number of wires significantly increases. In addition, it is necessary to add terminals for connection of the inertial sensors to a substrate (a relay board and a calculation unit) to which the inertial sensors are connected, and addition in the number of inertial sensors is difficult.
Further, in the robot shown in Patent Document 3, the torso is heavier and larger as the number of parts provided in the torso is larger. For example, in a robot having a movable torso, if control system components and utility system components are collected in the torso, load on an actuator for moving the torso may increase due to increase of inertia moment of the torso.